Making saggars.



No. 676,806. Patented lune I8, I90. A. WEBER, In.

HAKING SAGGABS.

(Application filed July 19, 1900.) (No Model.) 3 Sheets-Sheet L ,Z I l Iv 1! 1 .1. i I

i a a Z 14' 1 (z/4 677,045 sea: jrzmenaor:

mums vz1z== co PHOYO-LIYNG. msnmavm u c No. 676,806. Patented lune l8,l90l.

A. WEBER, In.

MAKING SAGGABS.

(Application filed July 19, 1900.) (No Mode!) 3 Sheets-Sheet 2.

aiwz 509% aims vzrzniicof. mmou'ma, msmnmou. n. c.

No. 676,806. Patented June l8, l96l.

A. WEBER, In.

MAKlNG SAGGARS.

(Application filed July 19, 1900.) (No Model.) 3 Sheets-Sheet 3.

UNITED Sa'rss AUGUST YVEBER, JR, OF SCI-IENEOTADY, NElV YORK, ASSIGNORTO AUGUST WEBER, SR., OF SAME PLACE.

MAKING SAGGARS.

SEEQIEIGATIQN forming part of Letters Patent No. 676,806, dated J nine18, 1901. Application filed July 19, 1900- Serial No. 24,171. (Nomodel.)

To all whom it may concern.-

Be it known that I, AUGUST \VEBER, Jr., a citizen of the United States,residing at Schenectady, county of Schenectady, and State ofNew York,have invented certain new and useful Improvements in Making Saggars, ofwhich the following is a specification.

The invention relates to such improvements; and it consists of the novelconstruciion and combination of parts hereinafter described andsubsequently claimed.

Reference may be had to the accompanying drawings and the referencecharacters marked thereon, which form a part of this specification.

Similar characters refer to similar parts in the several figures.

Figure 1 of the drawings is a central vertical section of the moldingapparatus used in carrying out my invention. Fig. 2 is a similar View ofparts of the die portions of the apparatus in the operation of molding asaggar. Fig. 3 is a similar view showing the inner die with the moldedsaggar thereupon withdrawn from the outer die or shell. Fig. 4 is asimilar view illustrating the manner in which the molded saggar isremoved from the inner die. Fig. 5 is a similarview showing the dieparts and the molded saggar fully separated from each other. Fig. 6 is acentral cross-section of a saggar formed by my improved method.

In the manufacture of porcelain articles the articles are made to assumeapproximately the desired form by means of dies or other apparatus andare afterward hardened by firing or subjecting them to extremely hightemperature in a kiln or furnace. In the operation of firing theporcelain articles, which while in a green state are delicate andfrangible, are placed in vessels of various forms to protect them fromthe direct action of the circulating heated gases in the kiln. Vesselsfor containing sucharticles during the firing operation are commonlyknown as saggars and are made of infusible clay shaped to hollow formand hardened by heat, and it is to the manufacture of these saggars thatmy invention particularly relates.

In the firing operation a large number of saggars filled with porcelainarticles are simultaneously exposed in the kiln, being placed one uponanother in stacks and the stacks arranged side by side to the fullcapacity of the kiln. These stacks are many feet in height, dependingupon the size of the kiln, and as the Weight of such a stack or columnof saggars and green porcelain is considerable the lowermost saggars inthe stack particularly are subjected to a great crushing strain.

The material of which saggars are made is an infusiblc clay of thenature of fire-clay, which in its natural state can be mixed with waterto form a plastic composition easily molded to any desired shape andwhich upon being exposed to a high degree of heat becomes of a more orless chalky nature affording little resistance to crushing force.Repeated firing orburningofsuch clay,however,greatly increases itshardness and strength, but destroys its plastic nature, so thatprecalcined clay cannot be formed into saggars without the addition ofsome plastic bond. For these reasons it is most desirable, if notnecessary, in making saggars to meet the conditions above named tocombine with a plastic mixture of natural clay and water a sufficientquantity of preoalcined clay reduced to fragmentary form to impart tothe saggar the desired strength, the plastic clay serving as a bond orunion for the precalcined-clay fragments. Several methods haveheretofore been employed in the manufacture of saggars, in one of whicha fluid mixture of clayis poured into molds, where it is retained untilthe moisture is evaporated,which requires a long time, rendering theoperation very slow. It is impossible by such a method to secure auniform product if the mixture contains precalcined-clay fragments, forthe reason that such fragments would not remain uniformly distributed ina fluid or semifluid mixture, such as is necessarily employed in thismethod. By another method the saggar is spun on a revolving table orpotters Wheel in the usual manner of forming pottery hollow Ware. Inthis method also the clay mixture must have a large percentage of waterto enable it to yield readily to manipulation, which fact, as well asthe usual difficulties of molding pottery, prevents the use of thismethod except for comparatively shallow articles. In this method it isalso impossible to use precalcined clay unless the same is reduced topulverulent form, as the engagment of a sharp fragment of precalcinedclay of any considerable size with the hand of the operator as themolded article is being rapidly rotated would tear away the surface ofthe article and numerous fragments of this kind would render the propermanipulation of the clay impossible. In the use of a precalcined-claymixture the strength of the product depends to a great extent upon thesize of the fragments to which the precalcined clay is reduced. Byhaving the fragments of precalcined clay of considerable size orthickness depending upon the thickness of the proposed saggar-wall mostof the fragments will contact with theirneighboring fragments andmaterially strengthen such wall not only in resisting a crushing strain,but in causing the freshly-molded saggar to retain its shape if removedfrom its forming-die while the plastic bond is yet plastie and undried.By the use of such a mixture I am able to make repeated and frequent useof a single set of dies for molding the saggars, because the moldedarticles can be removed from the dies at once and dried While whollyfree therefrom, producing a better unwarped saggar and largelyincreasing the producing capacity of a set of dies. Perhaps the mostcommon method at present in use is that of beating out a stiff mixtureof clayinto a sheet, which is applied to the surface of a wooden drum tosecure a cylindrical form, the ends of the sheet being oppositelybeveled and overlapped, the cylinder thus formed being applied to abottom disk formed of a similar clay mixture. The two parts thusassembled are placed upon a rotary platform and portions of the bottomand cylindrical side are worked together by hand to complete the body ofthe saggar. By this method much less water is used, which greatlyfacilitates the drying operation; but it will be seen that thecylindricalwall contains a joint or seam where its ends are boundtogether by simple adhesion of one to the other, while the bot tom andsides are connected by a similar seam or joint. Saggars so made arecapable of but limited use and almost invariably disintegrate along thelines of said joints and seams. In such a process it is possible to usefragments of precalcined clay of any considerable size; but when so usedsuch fragments do not lap the joints in the body of the saggar andafford no assistance in strengthening the saggar at these its weakestpoints. It is also practically impossible to secure a smooth finishedsurface on saggars so made, as it is impossible to force the plasticclay and precalcined -clay fragments into perfect surface alinement onthe body made by this method. I am also aware that earthenware articleshave been molded in dies and dried while supported inclosed in a diemember. Such a method is very slow in operation and could not besatisfactorily used in the manufacture of saggars such as I havedescribed, for the reason that one surface of the molded article beingprotected by the i'nelosing surface of the die member, while the othersurface of the article is freely exposed to the drying element,different parts of the article would shrink unequally in drying, causinga lack of uniformity in the texture of the product.

In the manufacture of saggars by my improved method I make use of amixture of plastic clay with precalcined clay in non-pulverulentfragmentary form, the fragments being of considerable size and, ifdesired, of different sizes for different sizes of saggar, which mixtureis so operated upon by the dies under pressure in the molding apparatusas to cause it to assume the desired form and to so distribute thefragments of precalcined clay throughout the body of the saggar thatsaid fragments shall form textural lines extending continuouslythroughout the bottom sides of the saggar and the molded article whenburned shall have a uniform texture throughout its bottom and sides.

Referring to the drawings, the apparatus for carrying out my inventioncomprises a bed or table 1, provided with supporting-legs 2, upon whichbed is secured a shell 3, forming the outer die member of-the moldingapparatus. The interior surface-lines of this shell are parallel andvertical. The interior of this shell can be given any cross-sectionalform which it is desired to impart to the exterior of the finishedarticle. This shell is provided with a movable bottom plate 4,corresponding in form to the cross'sectional form of the shell andadapted to reciprocate vertically within the shell. This bottom plate isfixed upon a reciprocatory rod or spindle 5, to which reciprocatingmovements can be imparted in any known manner, as by the treadle 6. Theupper inner die member is in the form of a plunger 7 of lesscross-sectional area than the interior of the shell 3 and is provided onits upper end with a flange 8 of a size and form adapted to closely fitthe interior of said shell. The body of the plunger 7 is adapted to formthe interior of the saggar and the flange 8 to form the top of the sidewalls of the same. The plunger is mounted upon the lower end of ascrew-threaded stem 9, which fits a similarly-threaded bearing 10 in theyoke 11, supported by uprights 12, erected from the bed of theapparatus. The screwstem is provided with an operating-handle 13,whereby the inner die member is adapted to be reciprocated into and outof the chamber Within the shell 3. The bottom plate L is preferablyprovided with a peripheral edge flange 14:, which is beveled at an angleof forty-five degrees, and the bottom edge of the plunger 7 is similarlybeveled at 15.

The operation of the apparatus is as follows: The desired quantities ofplastic clay and precalcined-clay fragments having been mixed togetherto the consistency of a stiE dough, a piece of the same containingsufficient material to form a saggar of the desired sizeis beaten orpressed out into a sheet or disk corresponding in contour with the shapeof the interior of the shell 3, and the plunger 7 being raised saidsheet or disk is placed within the shell in the position indicated bydotted lines 19 in Fig. 1, the bottom plate at resting upon the bed 1.The screw-stem is then operated by means of the handle 13 to force theinner die member within the outer die member or shell until the bottomof the plunger engages the plastic mass of clay. Further movement of theplunger causes the plastic material to be compressed between theplunger, bottom plate, and shell of the die, which material is thenforced to flow upwardly around the plunger until it engages the flange 8on the upper end of the plunger and entirely fills the mold-cavity, itbeing understood that the flange 8 is located within the shell andclosely fits the same to prevent the inclosed material from escaping.Bybevcling or chamfering the edges of the bottom plate and plunger theflow of the plastic material is facilitated. By thus causing the plasticmassto flow from the bottom to the sides of the molded saggar thefragments of precalcined clay are caused to assume lines extending inthe direction of the flow continuously from the bottom up the sides ofthe saggar such that when the saggar is afterward burned these lines ofprecalcined-clay fragments will formcontinuous textural lines in thefinished saggar. The plastic mass being thus confined on all sides bythe mold and subjected to pressure, the plastic clay and theprecalcined-clay fragments therein are forced into perfect alinementagainst the surface of the mold or die, which surface being smoothimparts to the molded article a perfectly smooth finished surfaceregardless of the size orquantity of precalcined-clay fragments contained in the mixture. The saggar having been thus given the desiredshape is removed from the molding apparatus by operating the screw toraise the plunger, while at the same time the bottom plate 4 is raisedby means of the treadle 6 in unison with the plunger, thereby carryingthe molded article 20, which remains upon the innerdie member, upwardlythrough the chamber of the shell 3 and exteriorly of the same to theposition shown in Fig. The bottom plate is then withdrawn to theposition shown in Fig. 1, leaving the molded article suspended upon theinner die member, as shown in Fig. 4, it being sustained upon saidmember by atmospheric pressure upon its exterior surface. The board ortray 16 is then placed on top of the shell 3 directly beneath the bottomof the molded saggar in position to receive the same when released fromthe inner die member. To quickly re lease the molded article from theinclosed die member, it is necessary to overcome the externalatmospheric pressure, and this I accomplish by introducing into thehollow of the molded article between'its interior molded surface and themolding-surface of the die fluid, as atmospheric air. This is preferablyaccomplished by forcing a small pin or awl 17 through the side wall ofthe saggar near the line of junction of the bottom and sides of thesame, the small hole thus formed permitting air to enter when the awl isremoved, thus equalizingthe external andinternalpressure upon the moldedarticle and permitting the same to be released from the die member bygravity while yet in plastic form and deposited upon the tray 16, asshown in Fig. 5. The saggar is then removed by means of the tray 16 tobe dried in any known manner entirely free from the molding apparatus,while the molding apparatus can be immediately used in repeating theprocess of manufacture. The hole 18 formed by the awl is so small thatits existence does not interfere materially with the use of the saggarfor all practical purposes; but, if desired, a small plug of clay can beinserted therein to fill the same. The molded saggar after beingsubjected to our rents of highly-heated air until the apparent moistureis evaporated is subjected to a firing or burning process, which expelsall moisture therefrom and causes the plastic clay to harden and form abond or union between the precalcinedclay fragments, thereby producing asaggar without joint or seam and of uniform texture throughout itsbottom and sides and which being formed in large part of precalcinedclay has maximum strength and durability. Saggars so made are able towith stand repeated firings. I

By removing the saggar from the mold in plastic condition I am able togreatly expedite its manufacture and can repeatedly use the sameapparatus for successive molding operations without any delay. Themold-cavity being wholly inclosed with no exit for the escape ofsuperfluous clay, the entire contents of the mold must be incorporatedin the mold ed article. It will thus be seen that by in" troducinguniform quantities of plastic material into the mold uniformity in thedimensions of the product will be secured. The quantity of material canbe exactly measured by weight.

The construction of the apparatus is such that by using the same diemembers the thick ness of the bottom of the molded article can be variedas desired by using a greater or less quantity of plastic material.

By the term precalcined clay in fragmentary form I wish to be understoodas referring to non-pulverulent broken fragments of precalcined clay.

\Vhat I claim as new, and desire to secure by Letters Patent, is-

1. A saggar or the like molded without joint or seam from a mixturecomprising a bond of plastic clay and non-pulverulent broken fragmentsof precalcined clay, the molded article being burned and of unifornrtexture throughout its bottom and sides,substantially as described.

2. A saggar or the like comprising a hollow body havingintegral bottomand sides molded without joint or seam from a mixture of plastic clayand non-pulverulent broken fragments of precalcined clay, the moldedarticle being burned and having textural lines of precalcined-clayfragments extending continuously from said bottom up said sides andbound together by the burned plastic clay, substantially as described.

3. That improvement in the art of making die-molded saggars, and thelike, which consists in removing the molded article from contact withthe molding-surfaces while yet plastic and undried, anddrying the moldedarticle free from contact with-such moldingsurfaces, substantially asdescribed.

4. The method of separating the die and the article molded therebyconsisting in puncturing the body of the molded article and ad- Initting fluid directly through such puncture between the contacting surfacesof the die and article.

5. That improvement in the art of making saggars, and the like, whichconsists in mixing with plastic clay non-pulverulent broken fragments ofprecalcined clay and molding the mixture to hollow form by die-pressure,substantially as described.

6. That improvement in the art of making saggars, and the like, whichconsists in mixing with plastic clay non-pulverulent broken fragments ofprecalcined clay, molding the mixture to hollow form bydie'-pressure,wholly relieving the molded article from contact withdie-surfaces while the plastic clayis yet plastic and subjecting themolded article to heat, substan tially as described.

In testimony whereof I have hereunto set my hand this 12th day of July,1900.

. AUGUST WVEBER, JR.

Witnesses: FRANK O. CURTIs, GEO. A. MOSHER.

